This invention relates to an apparatus and method for transporting liquids and dry powdered solids in collapsible containers and more particularly to a shipping harness for use with such collapsible containers which will allow them to be mounted in cargo boxes suitable for containerized use both in sea and land.
Traditionally, liquids, such as petroleum products, latex, dyes and powdered dry materials, have been shipped in metal drums, most commonly in 55 gallon steel drum. Such containers, if made of aluminum, stainless steel, or non-ferrous metals, are expensive, and if made of steel, tend to rust unless they are frequently cleaned and repainted. When chemically active fluids are shipped in such metal drums, the drums, by necessity, must be made of stainless steel or other non-reactive metals.
For shipment of large quantities of such liquids by sea, cargo tanks are commonly used which form an integral part of the cargo ships. They are loaded by pumping the fluid cargo from storage tanks, trucks, or other delivery means on the dock. The cargo tanks are located along the bottom of the ships and are covered by flooring on which conventional cargo is loaded. Such cargo tanks can normally carry between 30,000 and 100,000 gallons of liquid. When such tanks are used there is considerable delay in both loading and unloading of the liquid. The other cargo, wich is positioned over the tanks, must be loaded and unloaded by conventional techniques before the liquids may be added to or removed from the tank. This causes delay which vary from a matter of several days to up to 2 weeks at a time.
Recently stainless steel tanks approximately 20 feet long by 8 feet wide by 81/2 feet high have been used to ship such liquids. The tanks are mounted in protective cargo boxes of approximately the same size as the tanks. Loaded tanks in their cargo boxes may be transferred directly from the ship to truck or train beds. These stainless steel tanks are extremely expensive and of course are not collapsible. Thus, when they are returned to the filling point they represent considerable wasted space on board ship and thus a large resulting expense.
Collapsible containers, such as disclosed in U.S. Pat. Nos. 2,612,924 and 2,613,169, both issued on Oct. 7, 1952 to M. M. Cunningham, formed from coated cord fabrics have come into common usage for transporting liquids and dry powders. These containers have the advantage of being collapsible when not filled, allowing inexpensive return shipment to their point of origin. Such collapsible containers are formed from rubber or plastic compounds which are in general non-reactive with most cargos and which can be specially compounded to be non-reactive with specific cargos.
In general such collapsible containers, when used as transoceanic shipping containers, have had a 55 gallon capacity and have been shipped in the same fashion as 55 gallon metal drums. They are either wedged in place in a vertical position by use of sufficient containers to entirely fill the cargo area or are tied in position.
It would be preferable to use much larger collapsible containers to ship liquids by sea both for the ease of their return shipment and because of the cost advantage over the use of many small collapsible containers.
Some attempts have been made to use such larger collapsible containers for shipment of liquids on land. For example, in the patent to Erke, U.S. Pat. No. 3,510,142, a collapsible tank is disclosed mounted on the bed of a truck and having several straps positioned along its length to hold the container on the truck bed. The construction shown would allow considerable shifting of the liquid when the truck was in motion. Erke contemplates the loading of liquids into the collapsible container only after the collapsible container is mounted on its bed. It would be a difficult if not impossible task to move such a fully loaded collapsible container onto a ship. To load a collapsible container by pumping the fluid from the dock into an empty container aboard the ship would have little or no advantage over the existing tank system. Further even if it was possible to move such a loaded container onto the ship, the restraining means disclosed by Erke would be insufficient to prevent the motion of a ship from causing displacement of the non-rigid collapsible container with corresponding displacement of the other cargo, change in the ship's trim and the likelihood of rupture of the collapsible container.
It would be highly desirable to use one or more collapsible containers in a containerized cargo box which box would be suitable for positioning on ships fully loaded and which could also be moved from shipboard directly onto train or truck beds. However the use of such collapsible containers placed directly in containerized cargo boxes present serious problems. Shifts of weight during normal operation of a cargo vessel, truck or train would result in shifts in the position of the collapsible containers within the cargo box. Unless the cargo box was heavily reinforced, it would collapse due to such shifting. Such reinforcement would be impracticable because of the extra weight and expanse. This problem is particularly evident for shipboard use both because of the violent movement inherent in such travel and because, as a matter or economy, it is necessary that there be only minimal spacing of no more than several inches between the walls of the collapsible container and the cargo box in which it is mounted. This necessitates a system for mounting the collapsible container which allow essentially no movement of the collapsible container within its containerized cargo box.